Molan defends fed coup amid Wagga backlash

While senior members of the NSW government are blaming Liberal Party bloodletting in Canberra for a tight race in the Wagga Wagga by-election, federal Senator Jim Molan has defended the leadership coup.

Voters are heading to the polls in Wagga on Saturday with the NSW government bracing to lose the Riverina seat for the first time in more than half a century.

A troubled by-election campaign bookended by a local corruption scandal and a messy federal leadership overhaul has eroded the Liberals' once safe 12.9 per cent margin, senior government sources say.

But Senator Molan said the party needed to get rid of Malcolm Turnbull, and dismissed questions over whether federal Liberals would owe their state colleagues an apology if they lost Wagga. "I've seen no indication that that's even a factor," Senator Molan told AAP outside a polling booth in Wagga.

He said the government now had a "greater balance" under new Prime Minister Scott Morrison. While refusing to blame the Liberals poor polling in Wagga on the leadership spill, Senator Molan conceded people hadn't enjoyed watching another coup in Canberra. He said it was a necessary evil.

"People were very disappointed that we were spending time taking about ourselves and to ourselves but it's something that every now and again that you've got to go through," Senator Molan said.